We present a comprehensive multiwavelength temporal and spectral analysis of the ‘fast rise exponential decay’ GRB 070419A. The early-time emission in the γ-ray and X-ray bands can be explained by a ...central engine active for at least 250 s, while at late times the X-ray light curve displays a simple power-law decay. In contrast, the observed behaviour in the optical band is complex (from 102 up to 106 s). We investigate the light-curve behaviour in the context of the standard forward/reverse shock model; associating the peak in the optical light curve at ∼450 s with the fireball deceleration time results in a Lorenz factor Γ≈ 350 at this time. In contrast, the shallow optical decay between 450 and 1500 s remains problematic, requiring a reverse shock component whose typical frequency is above the optical band at the optical peak time for it to be explained within the standard model. This predicts an increasing flux density for the forward shock component until t∼ 4 × 106 s, inconsistent with the observed decay of the optical emission from t∼ 104 s. A highly magnetized fireball is also ruled out due to unrealistic microphysic parameters and predicted light-curve behaviour that is not observed. We conclude that a long-lived central engine with a finely tuned energy injection rate and a sudden cessation of the injection is required to create the observed light curves, consistent with the same conditions that are invoked to explain the plateau phase of canonical X-ray light curves of γ-ray bursts.
: The literature contains conflicting evidence regarding the existence of DNA damage in spermatozoa from infertile male patients. To examine this phenomenon, we have studied ejaculated spermatozoa ...from normozoospermic semen donors and from a group of the unselected male partners of couples attending an infertility clinic for initial investigation. Classical semen analysis according to World Health Organization (WHO) guidelines was undertaken with computer‐assisted sperm analysis (CASA). Spermatozoa were prepared by sequential washing and centrifugation and were analyzed for DNA fragmentation using three assays: 1) a single‐cell gel electrophoresis (comet) assay, 2) in situ nick translation with prior chemical decondensation (ISNT‐decondensed), and 3) in situ nick translation without prior chemical decondensation (ISNT‐condensed). In addition, reactive oxygen species (ROS) generation by spermatozoa was measured, and seminal plasma was analyzed for its total reactive antioxidant potential (TRAP). When the donor and patient groups were compared, the latter had lower levels of semen quality and higher levels of DNA damage, which was particularly apparent using the comet assay. Highly significant negative correlations were observed between DNA fragmentation, detected by all three assays, and semen quality, particularly sperm concentration. In addition, multiple regression analysis indicated that other attributes of semen quality, such as sperm movement and ROS generation, were also related to DNA damage. We conclude that a significant proportion of infertile men have elevated levels of DNA damage in their ejaculated spermatozoa.
We present a study of the early (days to weeks) X-ray and UV properties of eight Type Ia supernovae (SNe Ia) that have been extensively observed with the X-Ray Telescope (XRT) and UV/Optical ...Telescope (UVOT) on board Swift, ranging from 5 to 132 days after the outburst. SN 2005ke is tentatively detected (at a 3-3.6 slevel of significance) in X-rays based on deep monitoring with the XRT ranging from 8 to 120 days after the outburst. The inferred X-ray luminosity L sub(0.3-2) = (2 c 1) x 10 super(38) ergs s super(-1); 0.3-2 keV band is likely caused by interaction of the SN shock with circumstellar material (CSM) deposited by a stellar wind from the progenitor's companion star with a mass-loss rate of - 3 x 10 super(-6) M sub( )yr super(-1) (v sub(w)/10 km s super(-1)). Evidence of CSM interaction in X-rays is independently confirmed by an excess of UV emission, as observed with the UVOT on board Swift, starting around 35 days after the explosion. The nondetection of SN 2005ke with Chandra 105 days after the outburst implies a rate of decline steeper than L sub(X) 8 t super(-0.75), consistent with the decline expected from the interaction of the SN shock with a spherically symmetric CSM (t super(-1)). None of the other seven SNe Ia is detected in X-rays or shows a UV excess, which allows us to put tight constraints on the mass-loss rates of the progenitor systems.
Although cyclic diketopiperazines have been known since the beginning of the century, only now have they attracted considerable interest with respect to their biological activity. The aim of this ...study was to determine if the diketopiperazines cyclo(L‐histidyl‐L‐phenylalanyl) (cyclo(His‐Phe)) and cyclo(L‐histidyl‐L‐tyrosyl) (cyclo(His‐Tyr)) have significant biological activity relevant to the treatment of cardiovascular‐related disease states, cancer and infectious diseases. Haematological studies were performed, including thrombin substrate binding, blood clotting time, platelet adhesion, platelet aggregation and fibrinolysis assays. A cytotoxicity screening utilizing a tetrazolium‐based assay on the cell lines HeLa, WHCO3, and MCF‐7 was performed. The whole‐cell patch‐clamp technique was used to investigate ion‐channel activity in ventricular myocytes of rats, and isolated rat heart studies were performed to investigate the cardiac effects involving heart rate and coronary flow rate. Cyclo(His‐Tyr) produced a significant prolongation of blood clotting time, slowing of clot lysis and inhibition of ADP‐induced platelet adhesion and aggregation (P < 0.05). Cyclo(His‐Phe) showed significant (P < 0.05) anti‐tumour activity, causing greatest reduction of cell viability in cervical carcinoma cells. Preliminary results from patch‐clamp studies indicate that both diketopiperazines caused blocking of sodium and calcium ion channels, but opening of inward rectifying potassium ion channels. In the rat isolated heart studies, cyclo(His‐Phe) caused a gradual reduction in heart rate (P = 0.0027) and a decrease in coronary flow rate (P = 0.0017). Cyclo(His‐Tyr) significantly increased the heart rate (P = 0.0016) but did not cause any significant change of coronary flow rate (P > 0.05). Cyclo(His‐Tyr) showed notable (P < 0.05) antibacterial activity and both diketopiperazines showed excellent antifungal activity (P < 0.05). These observations reveal diketopiperazines to be ideal lead compounds for the rational design of an agent capable of preventing metastasis, inhibiting tumour growth, and as potential chemotherapeutic, antiarrhythmic and antihypertensive agents, as well as potential antibacterial and antifungal agents.
Positron Escape from Type Ia Supernovae Milne, P. A; The, L.-S; Leising, M. D
The Astrophysical journal. Supplement series,
10/1999, Letnik:
124, Številka:
2
Journal Article
Abstract
Study question
Emergency Fertility preservation in male patients- utilisation rate of the stored sperms and pregnancy outcomes
Summary answer
99% of men were able to cryopreserve their sperm ...before gonadotoxic therapy.9% of the sample were used and of them 62% had successful live birth.
What is known already
The testis is highly susceptible to the toxic effects of radiation and chemotherapy at all stages of life. Cytotoxic chemotherapy and radiotherapy may produce long-lasting or persistent damage to primordial sperm cells, leading to oligo- or azoospermia. Clinicians should inform patients receiving potentially gonadotoxic therapies about options for fertility preservation and future reproduction prior to the initiation of such treatment. The most common strategy to preserve fertility is cryopreservation of sperm before treatment for later use. Cryopreservation of testicular tissue from prepubescent males remains experimental.
Study design, size, duration
A retrospective analysis was performed in 367 patients who underwent emergency fertility preservation in our tertiary centre, during a period of 30 years between January 1991 to December 2021.
Participants/materials, setting, methods
An Infertility database for embryology and andrology s (IDEAS) was used for the data collection and analysis. Patient’s age, reasons for fertility preservation, type of cancer and benign conditions, sperm characteristics, whether the samples were utilized for fertility treatment and any treatment outcomes were included in the analysis.
Main results and the role of chance
The median age for the men who presented for fertility preservation is 30 years (Range 15- 55). The median number of straws is 9 (Range 1– 18). The referral was made from oncology (33%), haematology (28%) Urology (19%) and other departments (20%). The majority had a diagnosis was testicular cancer (50%), lymphoma (20%), leukaemia (5%) and other causes (25%). A total of 99 % of men had sperms frozen from the ejaculated semen and 1% underwent surgical sperm retrieval for cryopreservation. More than half the population of men at the time of cryopreservation were normospermic in 59%, the rest had oligo/asthenospermia in 40 % and azoospermia in 1 %. Cryopreservation was not possible in 1 % of the patients as they were unable to produce a sample. Nine percent of the sample were used for treatment and of them 62 % resulted in successful Livebirths. Intracytoplasmic sperm injection was the main treatment of choice. The mean Straws were perished electively in 2% and following death in 0.5 % of the study population.
Limitations, reasons for caution
Concerns about the welfare of resulting offspring, whether due to an expected shortened lifespan of the parent or effects of cancer or infertility treatment (in the present state of knowledge) ordinarily are not a sufficient reason to deny cancer patients assistance in reproducing.
Wider implications of the findings
The rate of use of cryopreserved sperm in cancer patients is low.Cancer patients were more likely than non-cancer patients to use or continue storage of banked samples. Sperm banks should be aware of the low rates of straw use and destruction by patients.
Trial registration number
not applicable
Considering the popularity of marriage enrichment programs, it is important for clinicians and marriage educators to know which programs have received empirical support. Using criteria established ...for determining empirically supported treatments (ESTs), we provide a comprehensive review of the outcome research on 13 specific marital enrichment programs. Only four programs could be considered "efficacious," three were found to be "possibly efficacious," and six were considered "empirically untested."
We describe the combined application of a transabdominal wall sheath tunnel, ‘pre‐close’ purse‐string sutures and manual external support of the iliac artery to facilitate introduction of an 18F ...sheath for endovascular exclusion of a 6‐cm thoracic aortic aneurysm.
There are distinctive methodological and conceptual challenges in rare and severe event (RSE) forecast verification, that is, in the assessment of the quality of forecasts of rare but severe natural ...hazards such as avalanches, landslides or tornadoes. While some of these challenges have been discussed since the inception of the discipline in the 1880s, there is no consensus about how to assess RSE forecasts. This article offers a comprehensive and critical overview of the many different measures used to capture the quality of categorical, binary RSE forecasts – forecasts of occurrence and non-occurrence – and argues that of skill scores in the literature there is only one adequate for RSE forecasting. We do so by first focusing on the relationship between accuracy and skill and showing why skill is more important than accuracy in the case of RSE forecast verification. We then motivate three adequacy constraints for a measure of skill in RSE forecasting. We argue that of skill scores in the literature only the Peirce skill score meets all three constraints. We then outline how our theoretical investigation has important practical implications for avalanche forecasting, basing our discussion on a study in avalanche forecast verification using the nearest-neighbour method (Heierli et al., 2004). Lastly, we raise what we call the “scope challenge”; this affects all forms of RSE forecasting and highlights how and why working with the right measure of skill is important not only for local binary RSE forecasts but also for the assessment of different diagnostic tests widely used in avalanche risk management and related operations, including the design of methods to assess the quality of regional multi-categorical avalanche forecasts.
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